origins of fragrance

[fandaal]

It has been shown that "pleasantness" is the main factor by which we classify smells in the perceptual space of 1500 odorants. The authors then invented various metrics for chemicals (atom counts, functional group counts, counts of types of bonds, topological descriptors etc.) The one that correlated best with the perceived pleasantness is a topological descriptor of molecular structure with no intuitive content: it is purely ideal, as it is the average eigenvector of the distance matrix, which is suitably normalized by molecular weight (that correlates with the volatility). Very crudely, it is a measure of the denseness of chemical bonds per volume of space. Using this approach they predicted pleasantness of 150 odorants and tested their prediction on their subjects, with moderate success, given the cultural variations and the fact that pleasantness is learned.

http://shkrobius.livejournal.com/148696.html